Webmaster Forum / Perl / Modules / September 2003

Hi,

Probably more of a basic ftp and (Shorewall) firewall configuration
issue, but I'll ask the question here anyway.

With the firewall running, and using the 'ftp' command line utility,
there's no problem. Here's a screenshot (debugging turned on):

ftp> cd w32perl
---> CWD w32perl
250 CWD command successful.
ftp> ls
ftp: setsockopt (ignored): Permission denied
---> PASV
227 Entering Passive Mode (203,59,24,225,7,225).
---> LIST
150 Opening ASCII mode data connection for file list
followed by a successful listing of all files.

But when I come to do the same thing with a perl script it doesn't work.

Here's the relevant section of the perl script:

 $ftp->pasv();
 $ftp->cwd('w32perl');
 @ret = $ftp->ls();
 $ftp->quit;
 for (@ret) {print $_, "\n"}

And here's the corresponding screen shot - again, the firewall is
running, debugging is turned on (and warnings are enabled):

Net::FTP=GLOB(0x82d98ec)<<< 230 User kalinabears logged in.
Net::FTP=GLOB(0x82d98ec)>>> PASV
Net::FTP=GLOB(0x82d98ec)<<< 227 Entering Passive Mode
(203,59,24,225,11,182).
Net::FTP=GLOB(0x82d98ec)>>> CWD w32perl
Net::FTP=GLOB(0x82d98ec)<<< 250 CWD command successful.
Net::FTP=GLOB(0x82d98ec)>>> PORT 203,220,176,129,134,163
Net::FTP=GLOB(0x82d98ec)<<< 200 PORT command successful.
Net::FTP=GLOB(0x82d98ec)>>> NLST

At this point the script simply hangs.
If I turn the firewall off there's no problem - so I guess that one
solution to the problem is to simply do just that before I run the
script. Another (better) solution would be to rewrite the script as a
series of system commands - but I would still like to know why the
operation works fine under one scenario, but fails under the other - if
only for the sake of my general education.

Of course I don't *really* want to have to turn the firewall off, and I
don't want to rewrite the script as a series of system commands either.
It would be far preferable to run the perl script as a Net::FTP script
if that can be done.

This is perl 5.8.0 on (mdk 9.1) linux, Net-FTP-2.65 btw.

Cheers,
Rob